Serotonin is made mainly from the amino acid L-tryptophan, which is found in large quantities only in complete
proteins and is highest in turkey
and other animal products. But a co-factor is B6, which is found in some vegetables, grains, and beans. Another co-factor is L-tyrosine, which also helps the body manufacture norepineprine, which stimulates, and is found also most in animal protein but also in any complete protein.